Shares of Apple closed at above $500 today, has a market capitalization of almost $470 billion

Apple shares closed above the $500 mark today, ending the day at $502.60. Impressive. Being the world's most valuable company must feel good, but being able to boast a market capitalization of almost $470 billion, must feel better.

This means they're up 9 points from yesterday's close, and up more than 80 from the day Apple released their numbers for their super-impressive quarter on January 24th. This $500 mark is said to be a 'psychological milestone', with the market cap the most important. $470 billion may sound like a lot, but during the 1990s boom, Microsoft, Cisco and GE also reached that height.

Considering Apple also hold close to $100 billion in cash, this goes to expand those numbers that little bit more. The question I have is, just like all companies, and empires, they fall. Will Apple continuously expand and hit $1000 per share? Or will they fall? What could do that? A true market crash? It seems nothing can stop this freight train that is Apple.